Frangipanis require warm weather and frost-free growing and grow best with warm mid-spring to early-summer plantings. Grow them outdoors in U.S. Department of Agriculture Growing Zones 10 and 11 and in large pots in colder zones. If you pot frangipanis, keep them outside from the last frost in spring to the first fall frost.
Site and Soil
Put frangipani seedlings in full-sun areas with quick drainage and protection from cold or drying winds. Start them with nutritious, crumbly foundations for good establishment and initial growth. Use well-rotted manure, organic compost or fire ash to amend outdoor sites, or pot in a mixture of enhanced, quick-draining soil and sand. Frangipanis do well in these rich mixtures, which encourage soil drainage but hold moisture between waterings.
The Sacred Garden Nursery notes that frangipanis grow through periods of neglect but thrive with careful nutrition and feeding. Use high-nitrogen, phosphorous and potassium fertilizers like 12-12-12 or 10-30-10 during the blooming season to encourage both growth and blooming. Feed frangipanis in early and late spring and again in mid-summer per manufacturer directions.
Frangipanis require more than rich nutrition and sunlight to grow. Maintain even, consistent moisture during the growing season with 2 inches of water every week. Dry frangipanis when they enter their fall and winter dormancy, and water them with only 2 inches of water every two weeks during this season. Resume regular watering and fertilizer applications in spring when new growth starts. Mix new compost into the soil in spring to wake frangipanis up and start them with long-lasting nutrition.